Poster communications
8-years time evolution of stratospheric HNO3 columns: investigation of the drivers of variability and of the link to O3
Abstract : Nitric acid (HNO3) is one of the main species involved in the stratospheric ozone cycles. Its spatial distribution was until recently only available from limb-sounding instruments but the IASI nadir-viewing sounder provides HNO3 concentrations distributions since 2007 with unprecedented spatial and temporal sampling.
In this presentation, we will briefly review the characteristics of HNO3 profiles retrieved from IASI measurements, in terms of vertical sensitivity and error budgets. The results from a validation exercise made by comparing the IASI-retrieved HNO3 profiles and columns with those from ground-based FTIR measurements will also be presented.
The focus of the presentation will then be on the time evolution of the HNO3 columns obtained from IASI measurements since the end of 2007. Global distributions as well as latitudinal time series will be shown and analysed, with a focus on total and stratospheric columns in the polar regions.
First results of a multivariable regression model will also be shown and discussed with regard to the main chemical and dynamical processes driving the seasonal and inter-annual variability of HNO3 concentrations. This will be done through the use of a regression model including dynamical variables accounting for the atmospheric circulation and other proxies accounting for the chemical reactions between HNO3 and other components of the atmosphere.
In addition to HNO3, IASI has the capability to measure accurate ozone columns in at least two stratospheric layers. This offers the possibility to analyse jointly the time evolution of the two species. Preliminary results from such a combined analysis will be shown, putting emphasis on the unexpected patterns of variability.
https://hal-insu.archives-ouvertes.fr/insu-01369321
Contributor : Catherine Cardon <>
Submitted on : Tuesday, September 20, 2016 - 6:01:28 PM
Last modification on : Saturday, December 12, 2020 - 12:10:04 PM
Contributor : Catherine Cardon <>
Submitted on : Tuesday, September 20, 2016 - 6:01:28 PM
Last modification on : Saturday, December 12, 2020 - 12:10:04 PM
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QOS2016-159_presentation.pdf
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